Chapter 3 Field Replaceable Units 15
3Field Replaceable Units
The field replaceable subassemblies within the Megaplex II chassis are described below. The
subassemblies in this section are:
• the power supply assemblies and
• the fan module assemblies.
These assemblies can be ordered as spares from AMI.

Warning

The 4U chassis has three power inlets; each one must be
removed to completely disconnect the power supply.
The 4U chassis contains a 5x20mm 250V 5A slow fuse
in the power supply.
Power Supply Modules Three 440 watt power supplies support the Megaplex II chassis. The power supplies are
located at the rear of the chassis. Each power supply has a power sharing board, which interfaces
to the power distribution board located internally in the chassis. DC power is distributed from the
power supply module to the power distribution board inside the enclosure and throughout the
chassis. Each power supply has an integrated fan.
These fans along with the additional chassis fans provide cooling for the chassis. Only the chassis
mounted fans are replaceable. Failure of a power supply fan requires replacement of the affected
power supply. To replace a power supply follow the procedure below.